Hello corey,
I have all bullnose corners in my house so I feel your pain. 
But the good news is that they are not as bad as you might think they are. You can even cheat like I did on my last addition and purchase the pre-made corners that match whatever molding you are using. You can get them for both inside and outside corners.
If they don't offer them in the style of molding that your going to use it's still possible. You just have to be a little more patients.
The outside corners are done by cutting the ends at a 22.5 degree angle and then adding in a small piece(approx 3/4" inside measurement) that both sides are cut at a 22.5 degree angle. This will create a 90 degree corner and give it a softer look and will fit pretty tight to the bullnose corner.
For inside corners I have used the same process just rounded off the back of the small piece a little to make it fit better. The other way that I like to do the inside corners is make my own corner blocks. I normally cut a square1/4" thicker and 1" wider than your chair rail and round off one corner to match the radius of the bullnose and then make a simple design at the top and bottom (1/2" each). Just enough to soften the look. This will let you cut a straight 90 degree angle to butt up against it at the corners. This can be a very simple look or you can make it a focal point of the chair rail.
I always glue the corners due to the small pieces will break if you try and nail them. Once all of the chair rail is installed complete the job by filling in all of the voids with a little bit of caulking.
Make sure and try a few before you start on your expensive moldings. The first couple can be tricky.
Let me know if you have any other questions. The community is always here to help.
