This is a job for screenprinting. I would see if anyone has created a vector for the pattern (or if you are able to copy it from reference images), since the pattern on the shirt and on the pants appears to be largely the same, just at different scale and arranged differently.
Screenprinting is the easiest way to get this level of detail in a design like this, and is likely how the original costume was created. This is a fairly simple and comprehensive tutorial on how to go about the process.
I hope that helps! Good luck :]