Both Sony HX5 and Nikon P7000 have 10.0 MP resolution sensors but Sony HX5's sensor is 1/2.4-inch (6.104 x 4.578 mm ) and Nikon P7000's sensor is 1/1.7-inch (7.44 x 5.58 mm ).
Since Nikon P7000'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 Sony HX5.
Below you can see the HX5 and P7000 sensor size comparison.
As seen above, Nikon P7000 has a 1.5x Larger sensor area than Sony HX5. 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.