Bring a large pot of lightly-salted water to a boil; add the pasta and cook until al dente, 8 to 10 minutes; drain. Place spaghetti in a large bowl.
Heat the olive oil in a skillet over medium heat. Cook and stir the chicken in the hot oil until browned; stir in the Italian seasoning and garlic and cook until the chicken is cooked through, about 5 minutes. Add the tomatoes and tequila; simmer another 5 minutes. Season with salt and pepper. Pour into the bowl with the spaghetti and stir to combine; serve immediately.