Preheat your oven to 400°F. If you have a convection setting, use it for an even cook. For easier cleanup, consider lining a baking sheet with aluminum foil and spraying it lightly with cooking spray.
In a medium bowl, crack the egg and whisk it gently with a fork until it's well-beaten. Add the chicken tenders to the bowl and toss them around, ensuring each piece gets a nice coating of egg. Set this aside for a moment.
Take a large ziptop plastic bag and fill it with the panko breadcrumbs. Once the chicken is coated in the egg, remove it from the bowl with a fork, letting the excess egg drip off, then drop the chicken into the bag. Seal the bag and give it a good shake to coat the chicken evenly.
If you prefer a more manual method, you can place the panko breadcrumbs in a shallow bowl. Dredge each piece of chicken through the breadcrumbs, flipping to coat thoroughly. This might take a little longer but can be satisfying!
Arrange the coated chicken pieces on the prepared baking sheet. Make sure they are evenly spaced and not touching, as this will help them crisp up nicely. If there are any leftover breadcrumbs in the bag, sprinkle them over the chicken.
Now, add the broccoli, cauliflower, and baby carrots to the sheet pan. Drizzle the vegetables lightly with olive oil and toss them with your hands to ensure they are evenly coated.
Sprinkle everything on the pan with lemon pepper seasoning, garlic powder, and if desired, a generous pinch of salt and pepper. Remember that many seasoning blends already have salt, so adjust according to your taste.
Slide the baking sheet into the preheated oven and bake for 20 to 25 minutes. During this time, the chicken will cook through, and the veggies will roast beautifully. You may want to check halfway through and flip the chicken and toss the vegetables for an even cook.
Once the chicken is golden brown and cooked through, remove the baking sheet from the oven. Optionally, garnish with fresh lemon wedges for an extra pop of flavor when serving.
Serve immediately and enjoy your wonderful Sheet Pan Lemon Pepper Chicken with family or friends!