Cook bacon in pan over medium-high heat until crisp. Remove bacon from pan, crumble and return to the pan. Add onion, and cook until tender, about 5 minutes. Add garlic, and cook until just fragrant. Add collard greens, and fry until they start to wilt.
Pour in chicken broth, season with salt, pepper, brown sugar & red pepper flakes. Reduce heat to low, cover, and simmer for 45 min, or until greens are tender.