Select the Sauté setting and add the bacon to the Instant Pot. Sauté for 5 minutes, until the bacon is sizzling and rendering some fat. Add the kale and salt. Sauté for about 2 minutes, until the kale has wilted down quite a bit.
Pour in the chicken broth, using a wooden spoon or spatula to nudge up any browned bits from the bottom of the pot. Add the cauliflower on top of the kale, arranging it in an even layer.
Secure the lid in the Sealing position. Cancel the cooking program, then select the Pressure Cook or Manual setting and set the cooking time for 2 minutes at low pressure. (It will take about 10 minutes to come up to pressure before the cooking program begins.)
When the cooking program ends, perform quick pressure release by moving the Pressure Release to Venting to release the steam.
Open the pot. Wearing heat-proof mitts, lift the inner pot out of the Instant Pot. Add the green onions. Using a potato masher, mash the cauliflower and mix everything together. Taste for seasoning, adding salt if needed.
Transfer to a serving dish and serve warm.