Unfortunately, the Microsoft Office Mobile for Android is not "officially" compatible with the Nexus 7 (2013) and cannot be installed from the Play Store. I've read that others have sideloaded it from the .apk file that some sources have made available on-line.
When I have a few spare moments, I may try to sideload it on my Nexus 7 to see if, and how well, it works. It is compatible with my Note II, so I will use it on that device to see if I like it better than Kingsoft Office, my current favorite office suite for Android.
Update: I sideloaded Office to my Nexus 7. It looks good and seems to run well. My next step is to work with some complex documents to see if "round tripping" those documents between Word 2010 on my Windows 7 machine and my Nexus 7 results in any loss of formatting fidelity.