Preheat the Instant Pot using the sauté function. Once it's hot, add the olive oil, onion, garlic, ginger and shiitake mushrooms. Sauté for several minutes, stirring occasionally, until lightly caramelized. Season the vegetables with salt and pepper.
Add the kale to the vegetables and continue to sauté until the kale is wilted. Add the miso-ginger broth and chile flakes. Continue to simmer on the sauté function for 5 to 7 minutes. Add the tofu and continue to simmer for another 5 minutes. The broth should be flavorful and aromatic. The tofu should be soft. Serve immediately or reserve for another day.