To his credit, Krugman has focused on pragmatic things like worker retraining, education, etc., but he also has called for tariffs [2].
Trump attempts to be seen as someone who adopts Reagan style deregulation and tax reduction, but in reality he has grown government spending and the budget deficit tremendously in his short time in office, and has created massive corporate welfare to many industries as well as steep taxes (in the form of tariffs) on firms that import goods from China, not to mention his threats of antitrust actions against tech [3].
Combined with the additional reductions in economic freedom that his trade deal adjustments with Canada and Mexico have wrought, he's ushered in tremendous bureaucratic overhead to oversee the process of making what are essentially superficial changes (yet which require tons of work by lawyers, etc. so that firms can comply). In general, a great deal of work and oversight for virtually no substantive benefit.
All this is pretty much exactly what Krugman has been calling for his entire career as a populist economist/columnist [4].
All of the below articles are Krugman making arguments that came later to be adopted by Trump as part of his rise to power. Note that Krugman's essays since Trump took office are blatantly partisan and largely nitpick Trump's execution of his ideas.
1. Krugman on the importance of the Rust Belt: https://krugman.blogs.nytimes.com/2013/07/21/a-tale-of-two-r...
2. Krugman calls for 25% across the board tariffs on Chinese goods: https://www.nytimes.com/2010/03/15/opinion/15krugman.html?sr...
3. Krugman on breaking up Amazon: https://www.nytimes.com/2014/10/20/opinion/paul-krugman-amaz...
4. Krugman on the failings of NAFTA https://www.nytimes.com/1993/11/10/opinion/in-america-nafta-...