Preheat oven to 350 degrees.
Sprinkle chicken tenders with salt, pepper, and dried rosemary. Keep in mind dried herbs are not as strong as fresh but you don't want to over do it either. Set aside.
Cut up broccoli and cauliflower, add to a large bowl.
Drizzle the veggies with olive oil. Add salt, pepper, and dried rosemary, toss.
Drizzle a large baking sheet with olive oil, spread the veggies evenly on the baking sheet.
Heat about 1-2 tbsps olive oil in a large skillet on high to medium-high heat.
Sear both sides of the chicken tenders to seal in juices and flavor. Do NOT cook the chicken through.
Transfer chicken to the baking sheet with the veggies.
Bake (roast), stirring once, until the veggies are tender and the chicken is cooked through, about 20-30 minutes.