The following article applies to Nexus Repository 2.8+.
Visit my.sonatype.com for documentation on Nexus Repository version 2.
In old Nexus Repository 2 versions, this was done by editing web.xml.
In Nexus Repository 2.8 and greater, this has changed.
You'll need to write a Nexus Repository 2 plugin which adds a Guice module. A good example that demonstrates this is: