Nim's network is already far more extensive than anything the Alliance has. What she is missing is things like hardware encryptors, burnable data nodes, and the kind of stuff that takes resources she never had before. Right now she uses ad-hoc encryption and private codes to communicate with her network over the public hypernet. The alliance might be able to, over time, provide gear that she never had access to before that would allow her to tunnel traffic, or maybe even make use of some private links to obfuscate locations a little over short distances. It's those kind of enhancements that could turn the excellent network Nim built by hand into a blaster-proof intelligence gathering net.
But that will take time, and budget. Right now, for the moment, Nim has neither. But if things go well here, she'll probably get a discretionary budget to shore things up.