in build.gradle in your project:

to publish:

publishing {
    publications {
        mavenJava(MavenPublication) {
            artifactId = artifactName
            from components.java
        }
    }
    repositories {
        maven {
            name = "NexusRemote"
            url = "http://domain.com:8081/repository/maven-releases/"
            allowInsecureProtocol = true // Required if you are not using HTTPS locally
            credentials {
                username = env.getProperty("NEXUS_USERNAME")
                password = env.getProperty("NEXUS_PASSWORD")
            }
        }
    }

need a .env file with environment variables & www. is a subdomain

// to consume:
repositories {
    mavenCentral()
    maven {
        name = "NexusRemote"
        url = "http://domain.com:8081/repository/maven-releases/"
        allowInsecureProtocol = true // Required if you are not using HTTPS locally
        credentials {
            username = env.getProperty("NEXUS_USERNAME")
            password = env.getProperty("NEXUS_PASSWORD")
        }
    }
}