Nexus does not use Wagons at all, but Wagon and it's related classes classes are needed on nexus-maven-bridge-plugin classpath as Sisu Maven Bridge (that nexus-maven-bridge-plugin encapsulates into nx plugin) requires Wagon (CNFs without them).

Legacy ITs use Wagons, see org.sonatype.nexus.test.utils.DeployUtils (no direct class reference but WagonFactory component is used to pick a Wagon instance). The nexus-test-harness-launcher module directly reference wagon-http-lightweight. Wagon is used _directly_, not with some Maven.