Your question is state specific, but the general rule is only the person making the contribution gets the deduction for the 529 contribution. So, it's not clear who gets the deduction (the money is now the child's money, but was originally the parent's
Contributions to a UTMA don't count, for a 529 deduction. But, transferring money form a UTMA to a 529 does count as deductible contribution.
Here is a link to NJ specific info:
https://www.savingforcollege.com/article/new-jersey-to-offer-529-plan-tax-deduction
Link to UTMA to 529 transfers https://www.merrilledge.com/ask/college/can-you-transfer-funds-from-529-plans
