I have seen but can't seem to find instructions on corner light replacement, such as the ones sold by Courtesy Nissan. Anyone bought these from them? How was the installation?

 

you can look in the car manual

 

Which corner light? the blinker?

 

if you are talking about the clear corner lights from courtesy, there is a write up in the how to section of 5thgenmaxima . I bought mine off ebay and I am pretty sure they are the same ones that courtesy sells. The install is easy, just go easy on the screwdriver when you pop out the old ones. You should be able to pick them up from ebay a few bucks cheaper than courtesy. I got mine from procarparts.com off of ebay. Search there and see what you come up with.