The chip labeled as 274 U141 031 hides the Bosch BMP180 MEMS Pressure Sensor, which should be responsible for the "Barometer" feature inside the Nexus.

The Bosch BMP180 is identified by its markings CMD 173 as noted by our friends at Chipworks.

Check out the wire bonds on the third image. This is a very, very small chip.

Just how small is it? Well, here's how a U.S. dime looks like next to the chip (indicated by red arrow)