NaCl doesn't have the low level networking capabilities needed for SSH, Telnet, etc. because they would be a security risk (a "game" could run a portscanner or look for open SMB shares on the network).
NaCl intentionally has the same sandbox, same security model, and same I/O capabilities as JS. In this case, NaCl would still be limited to XHR or WebSocket.
I'm not saying open it up to just anything, but if this is for ChromeOS, they could certainly grant access to manually-installed extensions (not extension gallery extensions) and/or to OS components.
Shhh, now that embedded Java does everything we need, we must pretend it no longer exists — how else could we justify all the insane technological contortions that we'll need in order to justify profiting through sequestering users' data, renting 1980s-era features to them, and selling their attention, intimate habits, and social bonds to advertisers?