“Trump on the issues that matter, immigration, border security, jobs, trade and nation security is far more conservative then Ted Cruz.”
Trump is a populist running on a conservative platform. Maybe he will govern conservatively. Or he may make pragmatic compromises that are very unconservative. While I disagree with Cruz on some issues, his conservatism is ideological which means he will stand up for principle like he has on amnesty and funding Obamacare and Planned Parenthood.
You'll see that Trump is actually a "nationalist" - which is very popular after so many years of America being run (to the ground) by those in both parties with a globalist agenda.
But since those calling themselves "conservatives" are actually "globalists," who do not want to bring attention to their total lack of nationalism, they call Trump a "populist" rather than a "nationalist."