Heat a tablespoon of olive oil in a skillet over medium-high heat, then sear the chicken thighs until golden brown on both sides — about 4-5 minutes per side. Transfer the browned chicken to the slow cooker.
Add sliced onions and minced garlic to the skillet and cook until fragrant and onions are slightly caramelized, about 5 minutes. Pour this mixture over the chicken in the slow cooker.
Chop your seasonal vegetables into bite-sized pieces and layer them around the chicken in the slow cooker. Toss in the fresh thyme for aroma, then season everything with salt and pepper to taste.
Pour the chicken broth over all the ingredients, ensuring the chicken is partially submerged. Cover and set the slow cooker to low, cooking for 6 hours until the chicken is tender and falling apart.
Once cooked, carefully remove the chicken thighs and shred the meat with forks. Return shredded chicken to the slow cooker and stir to combine with the vegetables and broth.
Taste the stew and adjust seasoning with more salt, pepper, or herbs if needed. Let it sit for a few minutes to meld the flavors, then serve hot in bowls with a spoonful of the rich broth and tender vegetables.