I just tested that and it does not work with my Navionics Hotmap Premium Canada chip. There are no overlay options available and I can't find a way to view the autochart live/lakemaster data with Navionics inserted. Once I pop Navionics out leaving just my ZLC, I have all sorts of options to use my satellite imaging or my acl/lakemaster map as the base and the other as the overlay. It also works with a real Lakemaster chip inserted.