Both Nikon P900 and Samsung Galaxy Camera 3G have 16.0 MP resolution sensors but Nikon P900's sensor is (1/2. ) and Samsung Galaxy Camera 3G's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Samsung Galaxy Camera 3G's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Nikon P900.
Below you can see the P900 and Galaxy Camera 3G sensor size comparison.
As seen above, Samsung Galaxy Camera 3G has a infx Larger sensor area than Nikon P900. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.