Pat the chicken thighs dry. Season both sides with 1/2 teaspoon salt, 1/4 teaspoon black pepper, the garlic powder, and smoked paprika.

Heat the olive oil in a 12-inch skillet over medium-high heat. Add the chicken thighs and cook without moving them for 5 to 6 minutes until golden brown on the bottom. Flip and cook another 4 to 5 minutes until cooked through to 165 degrees F. Transfer to a plate.

Reduce the heat to medium. Add the minced garlic and red pepper flakes if using to the same skillet. Cook for about 30 seconds, stirring constantly, just until the garlic smells fragrant. Do not let it brown.

Add the drained white beans and chicken broth. Stir and scrape up the browned bits on the bottom of the pan. Season with the remaining 1/4 teaspoon salt and pepper. Let the mixture simmer for 5 minutes, stirring occasionally. The beans will start to break down slightly and thicken the broth.

Add the torn kale in batches, stirring between additions so it wilts down enough to fit. Once all the kale is in the pan, stir to combine with the beans and broth. Cover the skillet and cook for 4 to 5 minutes until the kale is tender but still a little toothsome.

Nestle the chicken thighs back into the skillet along with any collected juices. Spoon some of the bean mixture over the top. Cover and simmer on medium-low for 5 more minutes until everything is hot and the flavors have blended.

Remove from heat and stir in the lemon juice. Taste and adjust salt if needed. Serve straight from the skillet with Parmesan sprinkled over the top if desired.