Why is the goddess Kali Niskama called

When does our karma come over?

Yes, what you sow you reap. But if you do (acts without attachment) you are not bound by this law.

In Shrimad Bhagavad Gita 3.9, Lord Krishna says:

यज्ञार्थात्कर्मणोऽन्यत्र लोकोऽयं कर्मबन्धनः।

तदर्थं कर्म कौन्तेय मुक्तसंगः 93.9 ।।

English translation by Swami Gambirananda

3.9 This man is bound to actions other than those intended for God. Without being connected, oh son of Kunti, you do deeds for Him.

English translation of Sri Shankaracharya's Sanskrit commentary by Swami Gambirananda

3.9 Ayam, that; Lokah, man, the one entitled to bargain; Karma bandhanah is bound by actions - the person who has karma as his bond (bandhana) is karma bandhanah -; anyatra, except; this karmanah, act; yajnarthat, definitely for God, not meant for God. According to the Vedic text "Sacrifice is truly Visnu" (Tai. Sam. 1.7.4) Yajnah means God; Whatever is done for Him is Yajnartham. Hence, without being bound, mukta-sangah is free from attachment to the results of actions; O son of Kunti, Samacara, you appear; Karma, actions; Tadartham, for Him, for God. An Eligible Person should also work for the following reason:

English translation of Ramanuja's Sanskrit commentary by Swami Adidevananda

3.9 The world is imprisoned by the bondage of work only when the work is done for personal use, not when the work is done or money is earned for the purpose of sacrifice, etc., as prescribed in the scriptures. So, in order to make sacrifices, you have to perform acts such as making money. As you do so, overcome ties created by pursuing personal ambitions and do your job in the spirit of yajna. When a person who is free from attachment is doing the work for sacrifice, etc., the Supreme Person who is appeased by sacrifice, etc., grants him the calm vision of self after destroying the subtle impressions of his karmas that have been since always beginning. Sri Krsna emphasizes the need to nourish the body only by the remains of sacrifices for those who devote themselves to all purposes of human life. He laments the sin of those who nourish the body by things other than the remains of sacrifices:

English translation of Abhinavgupta's Sanskrit commentary by Dr. S. Sankaranarayan

3.9 Yajnartha, etc. Binding are the actions that are different from what is Yajnartha, that is, those that are necessarily to be performed. The action that must necessarily be carried out will not produce fruit if it is carried out without attachment to the fruit.

Again in Shrimad Bhagavad Gita, 3.19 Lord Krishna says:

तस्मादसक्तः सततं कार्यं कर्म समाचर।

असक्तो ह्याचरन्कर्म परमाप्नोति पूरुषः।।3.19 ।।

English translation by Swami Gambirananda

3.19 If you are not connected, always do the mandatory duty, because by doing the duty without attachment a person attains the highest.

English translation of Sri Shankaracharya's Sanskrit commentary by Swami Gambirananda

3.19 Since this is so, Asaktah remains disconnected; Samacara, perform; Satatam, always; Karyam, the mandatory one; daily karma, duty; Hello, for; acaran, by performing; (one's) karma, duty; Asaktah, without attachment, working as a dedication to God; Purusah, a person; Apnoti, reached; Param, the Most High, Liberation, through purification of the mind. That’s sense. And (you should do your duty) also for the following reason:

English translation of Ramanuja's Sanskrit commentary by Swami Adidevananda

3.19 Given that work must be done remotely, do it by treating yourself as a non-agent. This is explained in the words "with distance" and "what should be done", which means that through karma yoga one attains the highest for oneself.

English translation of Abhinavgupta's Sanskrit commentary by Dr. S. Sankaranarayan

3.17-19 Yas ca etc. up to the Purusah. However, for a person who takes pleasure in himself and performs action simply as the [routine] business of action organs, there is no difference between (his) action and non-action. Therefore, he punishes or favors any being, not with a desire for gain for himself, but with the conviction that it is a thing that deserves to be done. Therefore, just disconnected, one should take an action that is to be carried out.

And you do, you are freed from the bondage of childbirth. It is said by Lord Krishna in Shrimad Bhagavad Gita 2.51.

कर्मजं बुद्धियुक्ता हि फलं त्यक्त्वा मनीषिणः।

जन्मबन्धविनिर्मुक्ताः पदं गच्छन्त्यनामयम्।।2.51 ।।

English translation by Swami Gambirananda

2.51 Because those who are devoted to wisdom and become men of enlightenment by giving up the fruits of action, attain the state beyond evil by being freed from the bondage of birth.

English translation of Sri Shankaracharya's Sanskrit commentary by Swami Gambirananda

2.51 The words "phalam tyaktva, by giving up the fruits" are connected with the removed word "karmajam generated by actions". Hello because; [For if actions are performed with an attitude of hostility, it will result in their being delivered from sin, etc. Hence it gradually becomes the cause of liberation.] Buddha-Yuktah, those who devote themselves to wisdom, who are imbued with the wisdom of hostility; (they) become Manisinah, men of the Enlightenment; tyaktva by giving up; Phalam, the fruit, the acquisition of desirable and undesirable bodies; [Desirable: the bodies of gods and others; undesirable: the bodies of animals, etc.] Karmajam generated by actions; Gacchanti, reach; Padam, the state, the highest state of Visnu, called Liberation; Anamayam, beyond evil, that is, beyond all evils; by becoming Janma-Bandha-Vinirmuktah, freed from the bondage of birth (Janma) itself, is bondage (Bandha); to be freed from it, even during life. Or: Since it (buddhi) was mentioned as the direct cause for the elimination of justice and injustice, etc., what was introduced (in the three verses) became, beginning with "O Dhananjaya", the yoga of wisdom '(49 ) is enlightenment itself, which consists in the attainment of the highest goal, which is like a flood all around and which arises from the purification of the mind as a result of karma yoga. [In the first part of the commentary, Buddha was understood as Samattva Buddha (wisdom of hostility). The alternative meaning of Buddha was taken as "enlightenment". The action must therefore be carried out with the help of the “wisdom about the highest reality” which was chosen as the goal.

English translation of Ramanuja's Sanskrit commentary by Swami Adidevananda

2.51 Those who have this equilibrium of mind while performing deeds and giving up their fruits are released from the bondage of birth and go to the region beyond evils. 'Hi' means that this dictum or teaching is known in all the Upanisads.

English translation of Abhinavgupta's Sanskrit commentary by Dr. S. Sankaranarayan

2.51 Karmajam, etc. The persons who are endowed with the determining faculty in relation to yoga renounce the birth bond by renouncing the fruit of the actions; and they attain Brahman existence.

And now you come to your second question

So if we forego the fruits of actions, there will be no sanchita karma (as I understand it).

Please note that this answer is based on BG only.