Hi

No NITs offer bsc in Mathematics or courses of such kind. NIT'S mostly offer engineering courses like and courses like PHD, b.arch, PGD, b.plan, m. Arch, m.plan. however there are some NITs which provide 5 years integrated course of B.sc and m.sc in Mathematics.  They are:

NIT rourkela

NIT patna

NIT surat

For more information visit:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.careers360.com/university/national-institute-of-technology-patna/msc-mathematics-integrated-course&ved=2ahUKEwif4oDj2cjyAhVJcCsKHcnnAJkQFnoECAQQAQ&usg=AOvVaw1R2bNG5I6b2MKKAdQMVl5J

Hope this helps