Williams is the 22nd player and the second edge rusher to commit to Penn State's recruiting Class of 2024.
The Nittany Lions open the season at home against national runners-up North Carolina.
Nickal was originally set for fight Tresean Gore before Gore pulled out due to injury.
Sturtz spent three seasons at Penn State as a forward from 2015-18.
The Nittany Lions will open the season against Le Moyne at Jeffery Field.
Penn State's global ranking of No. 83 is a bump from last year's ranking at No. 93.