Heat the olive oil in a large skillet over medium-high heat. Coat the chicken in the flour and then cook until golden brown on both sides (but still raw/pink in the middle). Remove from the pan and add to the slow cooker.
Deglaze the pan by adding the wine and turning up the heat to high while scraping the brown bits off the bottom of the pan (be careful of flare ups if using a gas range...you may want to turn the fire off momentarily while you pour the wine in). Cook for a few minutes until the wine is reduced by half, then pour into the slow cooker.
Add the onion, bell peppers, mushrooms, garlic, oregano, salt, red pepper, diced tomatoes, capers, and olives. Cover and turn the slow cooker onto low for 7 to 8 hours or high for 4 to 5 hours. Serve over whole-grain noodles or polenta.