I don't think it's a bad idea, but not sure if the juice is worth the squeeze:
"Indiana taxpayers may receive a state income tax credit equal to 20% of their contributions to a CollegeChoice 529 account, up to $1,000 per year ($500 for married filing separately) through December 31, 2022. Contributions by Indiana taxpayers made on or after January 1, 2023, will qualify for the 20% tax credit, with a new maximum of up to $1,500 ($750 for married filing separately)"
So you would put $7,500 in a year ($7,500 X 20% = $1,500) for 3 years? Total $4,500 tax savings? Not bad, but how do the rest of your investments look. Are you maxing out all other tax advantaged accounts (roth, 401k, hsa)? Do you have money in non-retirement accounts? Decent Cash Position? Interested in investing in real estate?
Personally, I would keep investing in the kids' 529 accounts (still getting the tax benefit outlined above) until those buckets are full and invest in other accounts/asset classes with any surplus.