Nose gear
In some cases, it just might mean that the nose gear strut is underinflated. These struts vary in design but many are basically pistons that use air and oil under pressure to remain partially extended under the weight of the aircraft. Depending on temperature, leaks, and perhaps just how much air was added during the last service, they may be slightly low or high.
I should mention that usually nitrogen is used rather than air when servicing the struts because it does not promote corrosion as much as oxygen and the larger molecules don't leake around seals as fast. (Regular air is 80% nitrogen anyway so not really much difference)
Also, depending on the last landing and perhaps bouncing during taxi, sometimes the struts just settle a little high or low.