Prepare the ingredients by cutting the potatoes and slicing the onion.
In a skillet, heat olive oil over medium heat and sauté the onion and garlic until softened.
Layer the potatoes in the bottom of the crockpot.
Place the sautéed onion and garlic on top of the potatoes.
Season the chicken thighs with salt, pepper, and oregano, then place them in the crockpot.
Pour fresh lemon juice over the chicken and add a splash of water if needed.
Cover and cook on low for 6-8 hours or high for 4-5 hours.
Check for doneness, then serve hot.