I don’t have a specific brand or model to recommend, but I really suggest getting an offroad helmet (which could protect your chin) if you are going to ride fast, even onroad (as in, not offroad).
The idea is, if you fall forwards in high speed (typical UPD situation), it’s unlikely you can land on your feet, and chances are you brake with your face. I had the exact accident yesterday, I fell at about 18km/h to dodge a randomly appeared pedestrian. I wore a standard bicycle helmet which did not have the chance to protect my chin. I ended up in the ER to get a few face wounds stitched, which the doctor says accumulates to 6cm.