Cut chicken into bite-sized pieces (about 1-inch cubes), season generously with salt and pepper, and toss to coat.
Melt butter in a large, nonstick skillet over medium-high heat. When butter turns brown and fragrant, add the chicken in a single layer and arrange sage over the chicken.
Set the timer for five minutes. Cook the chicken on one side without moving for 2 minutes and 30 seconds until golden brown. Stir and toss chicken and sage, making sure to coat all in brown butter, then flip the chicken to the other side and cook for the remainder of the time.
Serve with your favorite side dish, make quesadillas, or add to pasta.