Nelson made an appearance in all 16 of Penn State's game in 2024.
Clifford tallied 15 receptions for 266 yards and a touchdown last season as a redshirt junior.
The two signal callers played the majority of reps in Penn State's spring game as they vie for the backup quarterback job.
"There's an opportunity here to join the room and compete."
"If I never had this opportunity, I don't know where I'd be."
King became the fifth Nittany Lion selected in this year's draft.