You want to use Next Page breaks.
But know that if you're going to use Nookpress/Pubit to convert it to epub, they won't stick around. Your file will be formed into one long continuous file and you won't even notice those breaks, so I wouldn't bother with them.
The only way you're going to get the page breaks you're looking for is to format a verified, ready to upload, epub.
In microsoft word, use 'Insert > Break> Section break (Next page) and Nook Press will import those breaks as new chapters. =)