Preheat slow cooker to high.
In a large pan, heat olive oil over medium-high heat. Add in chopped onions and cook for 3-4 minutes.
Add diced chicken breast to a large bowl with chopped jalapeños, curry powder, ground coriander, chili powder, black pepper, kosher salt, ground ginger, minced garlic, garam masala, cinnamon, nutmeg, paprika, and an additional 2 tbsp of olive oil. Using your hands, coat the chicken with all the spices evenly. Add to pan with onions and cook for 4-5 minutes.
In your slow cooker, add chicken stock, sugar, coconut milk, diced tomatoes, and tomato paste. Stir until well-combined.
Add in onions + seasoned chicken breast. Cook on high for 4 hours or on low for 6 hours.
Serve over Minute Jasmine Rice + enjoy!