Assault and battery? Murder? That is protected by the supremacy clause?

Yep. One of the earliest and most important cases on the Supremacy Clause was actually a murder charge. In re: Neagle. Landmark case:

en.wikipedia.org - In re Neagle

U.S. marshall killed a man while the marshall was serving as the bodyguard for a SCOTUS Justice. State arrested the marshall to bring him up on murder charges. The Court said, "nope - man was just doing his job as directed by the President, and the state cannot restrict him from doing so."

Under the provisions of Rev.Stat. § 788, it is the duty of marshals and their deputies in each State to exercise, in keeping the peace of the United States, the powers given to the sheriffs of the State for keeping the peace of the State; aud a deputy marshal of the United States, specially charged with the duty of protecting and guarding a judge of a court of the United States, has imposed upon him the duty of doing whatever may be necessary for that purpose, even to the taking of human life.

https://supreme.justia.com/cases/federal/us/135/1/

Surprising, right? But that's the jurisprudence on the Supremacy Clause. It's not just a question of who gets to write statutes. All of the organs of federal government - the agencies and their personnel - are beyond the ability of States to regulate. Even with laws that apply to everyone and aren't at all intended to single out federal power, like building codes or license plate requirements - or penal codes prohibiting murder.

The main reason that a murder charge might be able to avoid the Supremacy Clause for the killing of Pretti and Good is if the courts determine they were acting outside of what was part of their federal duties.

I get the sense, though, that PhoolishPhilip is suggesting that states can use their power to push back on ICE in far less extreme circumstances. That they can use state law to stop ICE from conducting their raids in ways or using methods that are contrary to state law, even to the point of enforcing ordinary traffic laws against them in an effort to impede them somehow.

That's not going to fly. The operation of federal authority and the conduct of federal operations cannot be limited by state laws. If something doesn't involve federal authority or federal operations, or the state law doesn't limit them in any way, then the federal officials can be required to follow state law. But trying to use state law to slow down, impede, restrict, or resist the federal government doing something that involves federal authority or federal operations is just not going to work.