Cook the pasta according to package instructions. Drain and set aside to cool.
Grill the chicken breast until fully cooked, about 6-7 minutes per side.
Allow the chicken to rest for a few minutes before slicing it into bite-sized pieces.
In a large bowl, combine the cooked pasta, sliced chicken, cherry tomatoes, spinach, cucumbers, red onion, and bell peppers.
In a separate small bowl, whisk together olive oil, lemon juice, salt, and pepper.
Pour the dressing over the pasta salad and toss gently to combine.
Add the crumbled feta cheese on top and toss lightly again.
Taste and adjust seasoning, if necessary.
Chill in the refrigerator for at least 15 minutes before serving to allow flavors to meld.
Garnish with fresh basil before serving.