The Canon EOS Rebel T6 1300D has a smaller sensor (18 mega-pixels) than the Nikon D3300 (24 mega-pixels).
That is not the whole story. The Canon is a newer camera design with newer hardware. Canon designed it specifically for the entry level dSLR photographer. The Nikon D3300 is a three year old design and while still valuable (I use one) it does not have all of the newest features.
Its like trying to compare this year's Honda Accord with a four year old Jeep Compass because the dealer wants the same for both cars.