The Nittany Lions put up a seven-spot in the sixth inning to pull away with the victory.
Gaby Garcia tallied the first grand slam of the season in the mercy-rule win.
Johnson registered an average of 7.6 points, 0.2 assists, and 3.0 rebounds per game through 20 appearances and eight starts.
Nemeth led the blue and white to its first three-game sweep over Indiana since 1999.
"Ash has taught me so much. I've always been a fan of her game."