I like to hold a couple handfuls of greens out to add at the last minute, after the final simmer with the half and half. This keeps the color bright and enhances the texture. Spinach may also be substituted for one of the greens.
In batches, begin adding the chard and kale leaves, rotating them with a spatula as the leaves on the bottom begin to wilt. Continue to add more leave, carefully tossing so that all the leaves begin to wilt.
Add half and half, nutmeg, and salt and pepper to taste, and simmer a few minutes more.
Remove from heat and sprinkle freshly-grated cheese over the top.