Preheat oven to 400°F (200°C).
Trim the ends of the broccolini and toss with olive oil, half the salt, and half the pepper on a baking sheet.
Roast the broccolini for 12-15 minutes until the edges are charred and crispy.
While roasting, cook the pasta in boiling salted water according to package directions; reserve 2 tablespoons of pasta water before draining.
Season the chicken breast with garlic powder and the remaining salt and pepper.
Heat a non-stick skillet over medium-high heat and sear the chicken for 6-7 minutes per side until cooked through.
Let the chicken rest for 3 minutes before slicing into strips.
In a large bowl, combine the cooked pasta, fresh pesto, and reserved pasta water, tossing until evenly coated.
Add the sliced chicken and roasted broccolini to the bowl.
Finish with a squeeze of lemon juice and a sprinkle of Parmesan cheese.