Heat the olive oil in a large pot over medium heat.
Add the diced chicken and season with salt and pepper.
Stir in the minced garlic and cook for 1-2 minutes.
Zest the lemon directly into the pot, then squeeze in the juice.
Pour in the chicken broth and bring to a boil.
Add the linguine and cook according to package instructions.
Once the pasta is nearly al dente, stir in the chopped spinach.
Remove from heat and let it sit for a few minutes before serving.
Serve with freshly grated Parmesan cheese on top.