If you have an example of a sample title (preferably one with a free sample preview?) we can take a look.
If the books are illustrated, it may be hard or impossible to get what you want, if they were laid out for the NC.
If you're looking to increase text, tap the bottom of the page. A set of icons pops up; tap the Aa icon to get into your font and layout controls.
Be sure that "override publisher defaults" is set so that you control the font size.
Thank you so much for answering my question i think you are right that if a book is laid out for a nook color and not a nook hd+ then it probably will not confirm to it right. I did find the options under the Aa and tired to pick the size i wanted the page or the margins but that still didnt change anything but thank you so much for your help it really means a lot