Nickal was originally set for fight Tresean Gore before Gore pulled out due to injury.
Cunningham, a rising junior at State College Area High School, recorded a 28-7 record his sophomore season and placed first in the district and regional levels at 145 pounds.
The World Championships will take place starting Saturday, September 10, in Belgrade, Serbia.
Aaron Brooks, Nick Lee, and Jason Nolf took home U.S. Open Championships.
The 133-pound wrestler will likely fill the roster spot left behind by Penn State legend Roman Bravo-Young.
Mesenbrink notably beat now-fellow teammate Levi Haines twice in the US Team Trials to solidify his spot in the tournament.