Canon SX730 HS has a 20.3MP 1/2.3" (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features DIGIC 6 processor. On the other hand, Nikon A1000 has a 16.0MP 1/2.3" (6.17 x 4.55 mm ) sized BSI-CMOS sensor .
Canon SX730 HS's sensor provides 4.3MP more than Nikon A1000's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the SX730 HS and A1000 sensor size comparison.
Canon SX730 HS and Nikon A1000 have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.