Cut the chicken into bite-sized pieces and add to a bowl along with the garlic, salt and pepper. Toss the chicken until coated with the spices.
In a large skillet heat the olive oil over medium-low. Add the chicken and cook until done, about 10 minutes. Be sure to flip the pieces halfway through. Remove from the heat once cooked and toss with the parmesan.
While the chicken is cooking, add the pasta to the boiling water. Cook following the package instructions, adding the spinach with 1 minute left in the cooking process. Before draining, be sure to set aside 1/3 cup of pasta water.
Once the pasta is al dente, drain it and the spinach, adding them to the skillet with the chicken. Add the butter, parmesan and garlic powder, along with a bit of pasta water. Toss to combine. We want the pasta to feel somewhat saucy, so add additional pasta water until you get that consistency.