Pat the chicken breasts dry with paper towels. Season both sides evenly with kosher salt, black pepper, and garlic powder.
Heat 1 tablespoon of olive oil in a large skillet over medium-high heat until shimmering.
Add the chicken breasts to the skillet and cook for 6 to 7 minutes on one side without moving, until golden brown.
Flip the chicken breasts and cook for another 6 to 7 minutes, or until the internal temperature reaches 165°F (74°C). Remove the chicken from the skillet and cover loosely with foil to rest.
In the same skillet, reduce heat to medium and add the remaining 1 tablespoon of olive oil.
Add the minced garlic and crushed red pepper flakes. Sauté for 30 seconds until fragrant.
Add the chopped kale to the skillet and stir to combine with the garlic and oil.
Pour in the chicken broth, cover the skillet, and cook the kale for 5 minutes, stirring occasionally, until tender and wilted.
Remove the lid, stir in the lemon juice, and cook uncovered for 1 to 2 minutes to evaporate excess liquid.
Serve the rested chicken breasts alongside the sautéed kale.