We are going to look at some some definitions.
White nationalists are one of a group of militant whites who espouse white supremacy and advocate enforced racial segregation.
Muslim: a follower of Islam.
If a person identifies himself as a white nationalist, he is admitting to being a racist. All Republicans are not racist, but all racist are Republicans, hence the white nationalist and Trump connection.
One can be a follower of Islam, and not be a terrorist.
Thank you for taking the time to read this.