I started a UTMA account for my kid and now have a 1099 for him with small dividends (<$200). Do I add that as additional income to my taxes (filing jointly). Thanks.

[JohnB5677]

You do not have to file anything.  A child's unearned income beyond $2,200 is taxed at the parent's normal tax bracket.  The $200 does not have to be reported.

See   Tax on a Child's Investment and Other Unearned Income (Kiddie Tax)

[Hal_Al]

You do not report his/her income on your return. If it has to be reported, at all, it goes on his own return. If your dependent child is under age 19 (or under 24 if a full time student), he or she must file a tax return for 2021 if he had any of the following:

1.          Total income (wages, salaries, taxable scholarship etc.) of more than $12,550 (2021).
2.          Unearned income (interest, dividends, capital gains, unemployment, taxable portion of 529 distribution) of more than $1100.
3.          Unearned income over $350 and gross income of more than $1100
4.          Household employee income (e.g. baby sitting, lawn mowing) over $2300 ($12,550 if under age 18)
5.          Other self employment income over $432, including money on a form 1099-NEC

Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.

In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section.

If his only income is from interest and dividends, Alaska PFD or capital gains distributions shown on a 1099-DIV, there is a provision for entering it on your return, using form 8814. Enter at Less common income / Child's income.
But, it is usually best for him to file a separate return, as qualified dividends and capital gain distributions could be taxed at a higher rate on the parent's return.