Yes, The capital loss carryovers can be used to offset capital gain net investment income. Those carryover losses will offset the same type of investment income but will not offset other types of income that may be subject to the net investment income tax.
Please see the IRS information Questions and Answers about the NIT info at the following link:
https://www.irs.gov/newsroom/questions-and-answers-on-the-net-investment-income-tax
in particular section 17 which deals with the type of income that can be used to offset NIIT.
