In a medium skillet, put chicken in enough water to cover almost to the top. Add dried basil and kosher salt, cover, bring to a boil, reduce to simmer, and cook for 10 minutes.
When chicken is done, set aside to cool and clean out skillet.
In a large pot of boiling, salted water, cook pasta until just done following package directions. Drain and set aside.
Place skillet over medium heat, add olive and chopped onion. Cook until soft and translucent, about 7-8 minutes.
Chop chicken and put in a large bowl. Add the pasta, cooked onion, thawed peas, pesto sauce, 1 cup of shredded Parmesan, mozzarella cheese, salt and pepper to taste. Mix to combine well.
In a 9" x 13" casserole dish sprayed with non-stick cooking spray add the pasta, pesto, chicken, and cheese mixture, spread until even and top with 1 cup of shredded Parmesan cheese.
Put into pre-heated oven and bake for 20 minutes, or until golden and bubbly.
Recipe by Bear In The Pantry at https://bearinthepantry.com/wp/pesto-pasta-bake-chicken/