Start by chopping the onion and celery into small, uniform dice, and mincing the garlic. Set aside.
Place a large heavy-bottomed pot over medium heat and add a tablespoon of olive oil. Once shimmering, add the diced onions, celery, and minced garlic.
Sauté the vegetables, stirring frequently, until the onions become translucent and fragrant, about 5 minutes. The mixture should smell sweet and savory.
Add the bone broth to the pot along with the chicken thighs. Bring the mixture to a gentle simmer, watching for small bubbles around the edges.
Reduce heat to low and cover the pot. Let it simmer uncovered for about 20 minutes, stirring occasionally, until the chicken thighs are cooked through and tender.
Remove the chicken thighs from the soup and shred the meat with two forks. Return the shredded chicken to the pot.
Stir in lemon juice and season with salt and pepper to taste. Add chopped herbs like thyme or parsley for a fresh pop of flavor.
Give the soup a final taste and adjust seasoning or acidity if needed. The broth should be bright and flavorful, with a glossy surface.
Serve the hot keto chicken soup in bowls, garnished with extra herbs if desired, and enjoy its comforting warmth and nourishing texture.