Use the Set Curve Normal node in Z Up mode before the Curve to Mesh node.
If you’re using Blender prior to 3.4, then you can use my z-up-curve-tilt-nodegroup.
Also, ensure your Omega2 shape is on the XY plane. You can tweak its rotation by rotating it on the Z-axis in edit mode, using a Transform Node or by setting the curve tilt.
Good luck.