Can I claim my minor daughter who recently moved back in for the child tax credit by amending my return?

Explain "recently moved back in" because that is not enough information.   Where did she live for at least 183 nights in 2020?

Qualifying Child for the CTC

A child qualifies you for the CTC if the child meets all of the following conditions.

1. The child is your son, daughter, stepchild, eligible foster child, brother, sister, stepbrother, stepsister, half brother, half sister, or a descendant of any of them (for example, your grandchild, niece, or nephew).

2. The child was under age 17 at the end of 2020.

3. The child did not provide over half of his or her own support for 2020.

4. The child lived with you for more than half of 2020 (see Exceptions to time lived with you , later).

5. The child is claimed as a dependent on your return. See Pub. 501 for more information about claiming someone as a dependent.

6. The child does not file a joint return for the year (or files it only to claim a refund of withheld income tax or estimated tax paid).

7. The child was a U.S. citizen, U.S. national, or U.S. resident alien. For more information, see Pub. 519, U.S. Tax Guide for Aliens. If the child was adopted, see Adopted child , later