he's chickened out of getting regime change primarily.

in terms of shifting war goals, he's chickened out on getting back to the status quo from before the war.

rather than chickened out, the US is the sound loser of this war. the best outcome the US can negotiate for now is worse than what they could get before the war

Meanwhile Iran continues to blow up oil prices which is devastating for the entire world's economy, to say nothing of the USA's economy and especially Trump's popularity.

Dude, they still have a huge drone force, or otherwise there would be tankers sailing