Pat the chicken breasts dry with paper towels, then season both sides generously with salt, black pepper, garlic powder, and onion powder.

Optional: Heat olive oil in a skillet over medium-high heat and sear the chicken for 2-3 minutes per side until golden brown. Transfer the seared chicken to your slow cooker. If skipping this step, place the seasoned chicken directly in the slow cooker.

In a mixing bowl, combine the uncooked rice, chicken broth, fresh lemon juice, dried thyme, and dried oregano. Stir well to distribute the herbs evenly throughout the liquid.

Pour the rice mixture carefully over the chicken in the slow cooker, spreading the rice in an even layer. Make sure the rice is mostly submerged in the liquid. Arrange the lemon slices on top of the rice.

Cover with the lid and set your slow cooker to low for 6-7 hours or high for 3-4 hours. Do not lift the lid during cooking.

At the minimum cooking time (6 hours for low or 3 hours for high), check that the chicken has reached an internal temperature of 165°F using a meat thermometer. The rice should be tender and have absorbed most of the liquid. If rice seems dry, add 1/4 cup more broth and cook 30 minutes longer.

Remove the chicken from the slow cooker and set aside. Fluff the rice with a fork and taste, adding more salt or lemon juice if needed. Serve the chicken whole or shredded over the fluffy lemon rice, garnished with fresh chopped parsley.