Canon SX270 HS has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features Digic 6 processor. On the other hand, Nikon P310 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor .
Below you can see the SX270 HS and P310 sensor size comparison.
Canon SX270 HS and Nikon P310 have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Canon SX270 HS has 32% larger pixel area compared to Nikon P310, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.