Cook the ham in oil in a stock pot over medium-high heat for 5 to 6 minutes or until browned on all sides. Remove with a slotted spoon; set aside.
Add the onion and garlic to the stock pot; cook, stirring occasionally, until soft, 5 to 7 minutes. Add the vinegar, sugar, and red pepper flakes and cook, stirring occasionally, 2 to 3 minutes more.
Add the collard greens, in batches, and cook, stirring occasionally, until beginning to wilt, 2 to 3 minutes. Add the Fresh Express® Baby Kale Mix and cook, stirring occasionally, until beginning to wilt, 2 to 3 minutes.
Add the broth and bring to a simmer. Reduce heat to medium and cook until the greens are soft and most of the liquid is gone, 20 to 25 minutes. Taste and season with salt, pepper, and more pepper flakes as needed. Add the ham.