Trump ousted Waltz on Thursday and named Secretary of State Marco Rubio to the position on an interim basis. While US officials say they expect Trump to be in no hurry to fill the job on a permanent basis, a number of candidates have emerged, Reuters reported.
"I'm going to be naming somebody," Trump told reporters aboard Air Force One as he flew back to Washington from a weekend at his Florida club.
He said he expected to fill the job within about six months, and it could be Miller.
"I think he sort of indirectly already has that job. Because he has a lot to say about a lot of things. He's a very valued person in the administration, Stephen," said Trump.