FF,I'm trying to read between the lines not good at it but doing...

FF,

I'm trying to read between the lines not good at it but doing my best

Interested organizations may submit their capabilities and qualifications to perform the effort in writing to the identified point of contact not later than 2:00 p.m. Central Standard Time on December 15, 2020. Such capabilities/qualifications will be evaluated solely for the purpose of determining whether or not to conduct this procurement on a competitive basis. A determination by the Government not to compete this proposed effort on a full and open competition basis, based upon responses to this notice, is solely within the discretion of the government.

So what they're saying is, the submission is only for the Govt to evaluate whether they'll approve the proposed sole source contract.
If by any chance the competitors did submit and the Govt. find them qualified, they won't/can't (in accordance to anti-trust law) approve a sole source contract. However, it is still under NASA's decision who they're acquiring the proposed item from.