Can the cost of your nursing license renewal be deducted? If so, which category does it fit into (educational expenses, professional publications)?

Professional License fees are deductible for federal income tax purposes, but there isn't a very intuitive line on the tax forms for entering the amount.  If you are a W-2 employee, and are not reimbursed for your license fees, the amount would go on a Form 2106, and if you are self employed it would go on Schedule C to Form 1040.  In either case, what I do is go to "Other Expenses" and enter it as "Professional License Fee"

If you are a nurse in Ontario, just go to College of Nurses of Ontario website

Application & membership fees (cno.org)

it has detailed explanation of all fees. Most likely your RN renewal fee is an Annual membership fee, search for  Union, or Dues in your tax software, enter it there.

amount should go to 

• Line 212 – Annual union, professional, or like dues