How do you get into nursing informatics? I have been a RN for 2 years.

IT used to be you could just be an RN with an understanding of the concepts of a distributed computing system and be a nurse. The world has moved well beyond that level and you need a more formal skill set. Unless you are a "geek, or nerd" and have lived and breathed computers and coding for much of your life - though you'd not likely be in nursing.

Assuming you have a BSN look for online nursing informatics certificate or even a masters program, If you do not have a BSN consider starting a program and use informatics courses as part of your program.

in the mean while most hospital have a nursing / IT liaison committee (names vary) you should try and get appointed to the committee as a staff nurse. It allows you to understand the various issues and you can provide your input on how the system needs to work for you. More importantly you get to meet the people who make the decisions on hiring personnel.
Show your interest and skills in meeting, volunteer to be a superuser for your unit/area/specialty are good basic starting places.

I actually learned my basic concepts reading science fiction as a grade schooler reading Issac Asimov discuss "Brainiac." Dated specifics but the overall concepts were the knowledge I need to create my first informatics job.