I see that Katz has an average GMAT score of 621:

https://find-mba.com/schools/usa/pennsylvania/pittsburgh-katz

Is it still possible with a GMAT of 600?

My goal is to move to the US. I am working as an engineer but I would like to go into supply chain or operations management.

The one year MBA has a 600 cut off. If you apply to the two year MBA at Katz, you will have a better chance.

Yes I was planning on the two year MBA, not the one year.

It looks like the average GMAT on the Katz program is now 640:

https://www.katz.business.pitt.edu/academics/mba/class-profile

... that puts you at quite a disadvantage with a 600. What does the rest of your background look like? How much work experience do you have?

I have 4 years of work experience total, software engineer turned project manager. Do you suggest I take the GMAT again? Truth be told, I was under the weather the day I took the test and I am certain I could do better.

If you think you can do better, absolutely you should retake it. The closer you can get to that 640 average, the better. The higher you can get, more options would be available to you, not to mention potentially more scholarship money.