Johnson will join Kieger's coaching staff after being an assistant coach at the University of Miami.
Eziuka joins the No. 4 2026 class in the country, per 247 sports.
The game will take place on June 8 at Rate Field in Chicago.
The Nittany Lions will look to rebound after a disappointing season last year.
Two former No. 1 picks could join immortality next January.
Tunca is the sixth member of Mike Rhoades' 2025 recruiting class.