Preheat a Dutch oven on the stovetop over medium-high heat.
Add oil. Season chicken thighs generously with kosher salt and freshly ground black pepper, then place 4 chicken thighs skin-side down in Dutch oven. Do not overcrowd the pan.
Sear for 6 minutes. Flip and sear for 2 more minutes.
Remove chicken thighs from Dutch oven and let rest on sheet pan. Repeat with remaining 4 chicken thighs.
Add carrots to Dutch oven and sauté for 3 minutes.
Deglaze pan with lemon juice.
Add chicken stock, quinoa and and basil to carrots, and bring to a simmer.
Return chicken thighs and any liquid on sheet pan to Dutch oven. Cover and cook on medium-low heat for 20 minutes.
Remove chicken from pan. Add asparagus and red pepper, then cover and cook for 5 more minutes.