Season Chicken: Sprinkle the chicken breasts on both sides with ½ teaspoon kosher salt and black pepper.
Heat Oil: Add canola oil to a large skillet. Heat it over medium-high heat until the oil is hot and shiny.
Sear Chicken: Place the chicken breasts in the skillet. Cook for 5 to 6 minutes per side, until browned. Remove the chicken from the skillet and set it aside.
Make Balsamic Sauce: Add balsamic vinegar, honey, and Italian seasoning to a small saucepan. Simmer over medium heat for 8 to 10 minutes, stirring occasionally, until the sauce slightly thickens.
Prep Autumn Mix: Place the halved Brussels sprouts, cubed butternut squash, and diced apple in a mixing bowl.
Cook Vegetables and Apple: Add the Brussels sprouts, butternut squash, and apple to the skillet. Sprinkle with the remaining ½ teaspoon kosher salt. Cook over medium heat for 10 to 12 minutes, stirring occasionally, until the squash is tender and the Brussels sprouts are browned in spots.
Finish Chicken: Return the chicken to the skillet with the vegetables. Cook for 4 to 6 minutes more, until the chicken is cooked through and reaches 165°F in the center.
Slice Chicken: Remove the chicken from the skillet and slice it into thick pieces.
Plate and Sauce: Spoon the Brussels sprouts, butternut squash, and apple onto plates. Top with sliced chicken and drizzle with the honey balsamic sauce.