Suitable reagents for nitration of thiophene I know that for nitration of benzene we can use concentrated nitric and sulfuric acid. As furan and pyrrole are less aromatic than benzene, they can be protonated more easily and undergo polymerisation. We can use $\ce{AcONO2}$ and $\ce{AcOH}$ instead.

Give the order of aromaticity: benzene > thiophene > pyrrole > furan, I'm not sure whether thiophene is suitable for use with concentrated nitric and sulfuric acid.
According to this reference by Katritzky et. al (2005) (see below):


  Thiophenes  are  easy  to  nitrate  compared  to  other  five  membered  heterocycles.  They  react  with  mild  nitrating  agents  such  as  copper  nitrate. 


The reference further reports the nitration of thiophene to 2-nitrothiophene by nitric acid/Trifluoroacetic anhydride in 78% yield.

The classic $\ce{c HNO3/c H2SO4}$ conditions are too strong and likely to result in substrate degradation.

Reference:

Alan R. Katritzky, Eric F. V. Scriven, Suman Majumder, Rena G. Akhmedova, Novruz G. Akhmedov, Anatoliy V. Vakulenko, "Direct nitration of five membered heterocycles," ARKIVOC 2005, (iii), 179-191 (https://doi.org/10.3998/ark.5550190.0006.320).