Well, NDOS can mean different things. If those disks can be copied with DiskCopy for example, they can simply be turned into ADFs with Transdisk or AmigaExplorer.
But if they are copy protected (e.g. use a non-amiga track format), there is no way to create ADFs, even with a Catweasel. You could talk to the CAPS people, they can create IPF images from these disks. Or you could use WHDLoad to install the games to HDD and then copy the HDD installation to the PC.
However there is the RawRead program from Toni Wilen, it can create extended ADFs of non-amiga tracks. See Aminet.
Bye,
Thomas