Bring a large pot of salted water to a boil and cook the whole wheat penne according to package directions until al dente.
While the pasta cooks, dice the chicken breast into bite-sized pieces and season with sea salt and black pepper.
Heat the olive oil in a large skillet over medium-high heat and add the chicken, cooking until golden brown and cooked through.
Remove the chicken from the pan and set aside; add the cherry tomatoes to the same skillet, sautéing for 3-4 minutes until the skins begin to blister.
Add the minced garlic to the tomatoes and cook for 30 seconds until fragrant.
Reserve 2 tablespoons of the pasta cooking water, then drain the pasta and add it to the skillet along with the cooked chicken.
Stir in the basil pesto, lemon juice, and reserved pasta water, tossing everything together until the pasta is well coated and glossy.
Garnish with freshly chopped basil leaves and serve immediately.