Bring a large pot of salted water to a boil and cook the whole wheat linguine 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 and cooked through.
Remove the chicken from the skillet, let it rest for 3 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 to the skillet and toss for 30 seconds until just wilted.
Drain the linguine, reserving 2 tablespoons of the pasta water, then add the pasta to the skillet.
Stir in the basil pesto, sliced chicken, and reserved pasta water, tossing everything together until the noodles are silkily coated.