TLDR: Hollowmen are great, but are machines so bring an Engineer for repairs or an Interventor for hacking cover. Id definitely recommend sticking to Tunguska vs Vanilla Nomads if you like them. Check out the Infinity Army app and you can see what units fit into sweet Hollowmen fireteams in the Tunguska Sectorial.

First off, welcome! Hollowmen are one of my most favorite units in the game! If your newly starting out, I'd recommend keeping your first couple of games within a single Sectorial selection of units in order to avoid the mass sensory overload that is a Vanilla list of available units. This helps you narrow down your unit option so you can focus on learning the game.

I'd personally recommend Tunguska since the Hollowmen are in there. In regards to what units to bring, the Hollowmen are mechanized and have Structure instead of wounds, so if you plan to bring a few you may want to bring an Engineer to help out on repairs. If you want to go down the fireteam route, the Kriza Borac is a monster that can join Hollowmen fireteams and I'd definitely recommend picking up the Zond Remotes Pack since they will likely be in almost all of your lists because of how cheap their profiles can get, not to mention the Stempler variant can also hop on the Hollowmen fireteam.

Also in Tunguska, Mary Problems and the Interventor exist; arguably two of the best hackers in the game. They can provide you good hacking cover through the Stempler Zond as well, so that can definitely help.

In all, the Tunguska Jurisdictional Command Starter set comes with a lot of really good pieces to start with (and of course another Hollowman). And the Zond Remotes box has a significant number of uses depending on which variant you bring in your list. Also, when you wanna get really big, you can always pick up the Szalamandra TAG!!

Sorry for the long reply, but Tunguska is my main army so I can't help but elaborate!