Bring a large pot of salted water to a boil and cook the brown rice penne according to package directions until al dente.
While the pasta cooks, season the chicken breast with sea salt and black pepper on both sides.
Heat the olive oil in a large skillet over medium-high heat and sear the chicken for 5-6 minutes per side until golden brown and cooked through.
Remove the chicken from the skillet, let it rest for 2 minutes, then slice it into thin strips.
In the same skillet, add the minced garlic and sun-dried tomatoes, sautéing for 1 minute until fragrant.
Add the baby spinach and a splash of pasta water to the skillet, stirring until the spinach is just wilted.
Drain the pasta, reserving a small amount of water, and add the pasta, chicken, and sun-dried tomato pesto to the skillet.
Toss everything together over low heat until well-coated, adding a splash of reserved pasta water if needed for a silky consistency.
Garnish with fresh chopped basil before serving.