A single system can have a dozen planets with bio-signatures, and the number of species on each might not be just two or three, but ten or more. Over time, all these transitions from ship to ship will drain you
In practice you don't generally need to dock the Nomad between bio species more than (occasionally) once, even on a 10-bio body. If you choose your point of descent carefully, it's almost always possible to glide down to a place where all the species are in reach via boosting around in the Nomad more quickly than they would be by returning to SC (even if Nomad was itself SC-capable).
For example, let's say you have concha, fungoida, frutexa, cactoida in sunken caldera areas, flat plains inhabited by stratum, aleoida, osseus, bacterium (and also cactoida), and on the hills and mountains you find tussock and clypeus.
As you descend you cycle between species in the DSS view, noting which areas are next to which as the planet comes closer. In the example I'd be looking for a caldera next to a mountain and choosing a direction of approach that would take me from one to the other and also (at some point) traverse the plains area where osseus etc. can be found.
Having found the approach, I take a mental note of the compass bearing during the final glide, so that I know which direction to proceed after wandering around locating individual bios, and then just tick the bios off one by one while sticking roughly to the line envisaged during descent. Doesn't always work out perfectly but needing to head into SC and back more than once before leaving would be quite unusual for me.
This isn't unique to the Nomad - I'd do the same in any ship. But I will say using this technique I was able to place top 10 in the recent CG, all scans done during the time it was active, in a Nomad ferried around inside a Cutter (of all ships!) This, incidentally, came about not out of any masochistic urges on my part but because I accidentally purchased Arx for the Nomad in the wrong frontier account, decided to go with it, and used the only ship that account had lying around with vessel bay support (discounting an Anaconda for reasons of taste.)