After installing Nexus Repository Manager OSS 3 I do not see option Artifact Upload to upload artifacts through web page.
Artifact Upload
In Nexus Repository Manager OS
For Windows:
mvn deploy:deploy-file -DgroupId=joda-time -DartifactId=joda-time -Dversion=2.7 -Dpackaging=jar -Dfile=joda-time-2.7.jar -DgeneratePom=true -DrepositoryId=[Your ID] -Durl=[YourURL]