For people with computer experience, an excellent text editor is Jota.(Say "ee-YO-ta"; Google Play description's info on pronunciation is not for English speakers, or was not, a while back..) It has a bunch of syntax choices for quite a few computer languages, so it should be quite nice for writing code.
abc Editor is also worth trying. There's also at least one good hex editor; iirc, its icon is an Android, but black.
A very nice twin-pane file manager is Ghost Commander. If you like descendants of Norton Commander, you'll be happy with this, more than likely. Do note that to select a file, click toward the right end of the listing for it. Clicking toward the left tries to open it. You might have a look at File Manager HD, also.
For photo editing, try Photo Editor; you might be pleasantly surprised. The little triangle at the bottom middle of the image gives file access.
Adobe has adapted Elements ($10, iirc), but it keeps files where you can't get at them to move them elsewhere. It also relies on icons without text labels.
There are oodles of compass apps, a few even in 3-D, because the magnetometer is 3-D.
As well, there are some very nice GPS apps; one might be called GPS Test, although it's quite practical. The GPS receiver is quite sensitive, giving a fix indoors (flat roof, single story).
If you want a real-time audio spectrum analyzer, there's a spectacularly good one, paid; icon is a blue mini-screen. Peaks are labeled with their frequencies. Name might include "fast". It creates a waveform of amplitude vs frequency, and refreshes fast. Touch (pinch, stretch, and move) works on the display. I had it nicely separating peaks 70 Hz apart at about 3 kHz. (There's a spurious internal signal around 6.9 kHz, iirc!) Windows and other key parameters are selectable.
Sorry not to have more accurate info, but I was seriously stupid not to get a bump protector, and mine fell face down. A used 8 GB N 7 and swapping its display and digitizer looks like the way to go. (Replacing just the digitizer alone is surely not for amateurs, imho.)
By all means, try Compass Mode in Maps --> Street View. The compass might be wildly out of cal. If that happens, try waving the Nexus repeatedly along the path of an infinity symbol, and allow its plane to tilt easily as you do it.