[Nexus Player Q&A, Help & Troubleshooting] jaypm:
i can confirm this approach as i have it all working now. elrondolio provided links with all the necessary information, but as someone that was new to flirc there were still a few things i had to figure out to put it all together. here is a distillation of what you need to know if you want to use flirc for IR control of the nexus player via a logitech harmony remote (in my case, the old but trusty harmony 650):

1) buy the flirc USB IR receiver dongle, still on sale for $14.95, not sure how much longer this will last.

2) buy a micro-USB adapter for flirc. this one works great and fits next to my HDMI cable, but be mindful that some HDMI cables with fat heads might crowd the adpater. costs $2 plus shipping.

3) add the nexus player to your harmony remote as a "Media Center PC > Flirc > XBMC" device as per these instructions. setup button mappings (as you prefer) that you will use for nexus player "back" and "home" buttons. in my case, i assigned the XBMC "back" command to the "previous channel" button on my remote. harmony remotes don't have "home" buttons and neither does the XBMC profile, so you need to pick something arbitrary here. i decided to assign the "PageUp" command to my harmony's "Menu" button, with the intention of mapping that command to the the corresponding keyboard combo for nexus player's "home" command in flirc (more on this in step 6). save and update your harmony remote with the new config.

4) plug your flirc+adapter into the nexus player and you should see partial functionality start working immediately. arrow keys and selection will work, back and home will not.

5) install the flirc desktop app for windows/mac/linux using these instructions.

6) plug flirc into your desktop computer and start the app to reprogram keys. reprogram as follows:

- switch to keyboard view by selecting Controllers > Full Keyboard.

- un-map the "back" button, since we need to re-map it. do this by clicking "erase" and then pressing the "back" button on your harmony remote (probably mapped to your "previous" button; check your harmony button mappings to confirm).

- map your harmony "previous" button to the "escape" key. do this by clicking on the "escape" key on the flirc keyboard image, and then pressing your "previous" button on the harmony remote (which sends the "back" command). the flirc app should say that the key was successfully mapped.

- map your harmony "menu" button to the "alt+escape" key. do this by first clicking the "alt" key on the flirc keyboard image, then clicking the "escape" key (both should now be highlighted), and then pressing your "menu" button on the harmony remote (which sends the "PageUp" command). the flirc app should say that the key was successfully mapped.

7) plug flirc back into your nexus player and you should now be able to fully navigate the nexus player UI.

there is one significant caveat that i have still not yet resolved, which is that the back and home button mappings do not necessarily work as expected under all apps. for example, the "back" button did not behave as expected in the TED app, and the "home" button doesn't work in XBMC. if/when i am able to resolve these minor issues i will post more updates here.