Add the wine and stir until almost evaporated, then add the chestnuts and start adding the broth gradually, about ½ cup at a time, stirring quite often and waiting for each addition to be absorbed before adding the next. If needed, reduce heat to a simmer.
When you have used about 3 cups of broth, add the milk and start tasting the risotto to determine when it’s ready. At this point, you may or may not need the extra cup of broth.