In a large mixing bowl, combine the olive oil, lemon juice, honey, lemon pepper seasoning, kosher salt, and black pepper. Whisk until well combined.
Add the bite-sized chicken pieces to the marinade, ensuring each piece is well coated. Cover and let it marinate for at least 30 minutes, or refrigerate for up to 2 hours.
Preheat your oven to 400°F (200°C).
Prepare the vegetables by tossing the broccoli, bell pepper, and red onion with olive oil and lemon pepper seasoning.
Line a large sheet pan with parchment paper and spread the marinated chicken on one side and the seasoned vegetables on the other.
Roast in the oven for 20-25 minutes, stirring halfway through cooking.
Remove from the oven, let cool for a few minutes, and serve warm.