I'm working on this too, but don't have all the simple answers. Its quite tricky. Android NFC implementation is a bit googley
If you format the message from the NEXUS in the compatible way the NFC board may read it. E.g NDEF message in a Mifare emulated tag.
I've been testing it more the other way. Try to emulate a tag dynamically from the 'Duino and then read it on the Nexus.
Switched to Felica (NFC-F) from Mifare (NFC-A) temporarily cos of frustration.
Testing out ideas, with libNFC on a Linux/Mac/Win box and a USB/UART connected board seems a good way to try stuff out and has clear examples,
for instance the one called 'nfc-emulate-forum-tag2'
does what you wanted to do.
Doesn't solve the Arduino coding, but will show a proof of concept.