@stephen tracy what type of visa do you have?
What reason do you have to attend immigration?
If you have a multi entry visa you would not need to make a TM30.
If you obtained a visa exempt entry in Nong Khai the only reason you would need to do a TM30 is if planning to attend immigration for extension.
If that's the case just do TM30 prior to attending immigration.
No urgency.