1. Boil pasta in a pot until al dente or preferred consistency, then strain out the water.
2. Heat a pan to medium heat, then pour in about a tablespoon of olive oil and add the diced chicken thigh. Add black pepper and stir fry until the chicken turns golden brown.
3. Add spinach and minced garlic, and stir fry for about a minute or until the spinach starts wilting.
4. Add the pasta and more olive oil. Stir to mix everything together.
5. Add lemon juice and stir again.
6. Add grated mozzarella cheese and mix until the cheese has melted. Serve warm.