I don't think I can deduct anything. I know I don't claim her as a dependent on my taxes and that seems to be the starting point for many things. We aunts get the short end of the stick there. It sounds like I may as well bite the bullet and pay the taxes.
Speaking as a "not a tax expert," I can't think of any situation where you can help with your niece's college expenses and have it be a tax advantage for yourself. However, do a little research and see if either gifting the money directly to your neice or to her parents might allow some tax advantage to any of them when she or they pay the college bill.
I'm taking a three step approach to helping my 3 grandkids with college.
1. I contribute the max $2k/yr each to their Coverdale Educational IRA's. Their dad, my son, owns the accounts so technically I'm gifting the money to him and he's making the contributions. In actuality, I do it all with linked accounts at Schwab. Those accounts work somewhat like a Roth IRA. No deduction, but withdrawals for educational expenses (both principal and earnings) are tax free.
2. I'll gift them up to $12k/yr (current gift tax exclusion) as necessary while they actually are in school.
3. Needs beyond $12k/yr will be made directly to the school to avoid triggering any gift tax.
Of course, this all assumes DW and I are able to plod along through retirement as we have been with no/few more additional recessions or other setbacks driving our retirement portfolio to be a FireCalc failure! Only time will tell.
BTW, we grandparents don't get any tax breaks for grandkids that you aunts don't get for nieces and nephews........
Edit: Looking back at my post, a little clarifying is in order. The Coverdale IRA's (probably will be $40k - $50k in today's dollars) will be there for each grandkid when, and if, they start post secondary school. Additional funds are not a commitiment made to them apriori, but rather a commitment made to my son, their father, that I'd pay for the kid's college if required. Hey, if they get schlorships, need based aid or participate in co-op or work-study programs and don't need Papa's dough, no problem with me! This has allowed DS and DIL to focus on retirement funding and on the expenses of having a special needs child without feeling they'll never be able to help with the kids college if required. It's kind of a team thing.......