How to change primitive node colors, gltf 2.0 vs gltf 1.0

CesiumJS
2

I figured it out!

Choose your primitive containing the node

var primitive = viewer.scene.primitives._primitives[0];

View node names like this

Object.keys(primitive._nodesByName);

Choose the node to be colored (1st one in this example)

var nodeName = Object.keys(primitive._nodesByName)[0];

Change the node’s color like this!

primitive.getNode(nodeName)._runtimeNode.node.primitives[0].material.metallicRoughness.baseColorFactor=Cesium.Cartesian4.fromColor(Cesium.Color.RED);

I got inspired by these posts :
Changing material of single mesh in model
How to color specific part of Model