A nano-sensor for nitrotyrosine (NT) molecule was found by studying the interactions of NT molecule with new B24N24 nanocages. It was calculated using density functionals in this case. The predicted adsorption mechanisms included physical and chemical adsorption with the adsorption energy of −2.76 to −4.60 and −11.28 to −15.65 kcal mol−1, respectively. The findings show that an NT molecule greatly increases the electrical conductivity of a nanocage by creating electronic noise. Moreover, NT adsorption in the most stable complexes significantly affects the Fermi level and the work function. This means the B24N24 nanocage can detect NT as a Φ–type sensor. The recovery time was determined to be 0.3 s. The sensitivity of pure BN nanocages could be improved without additional expensive structural manipulations. After the NT had been absorbed into the nanocage, UV–Vis spectrum analysis revealed that the transmission wavelength shifted significantly toward 390.07 nm. Hence, a redshift occurs when the NT molecule gets near the B24N24 nanocage. According to the present study model, B24N24 nanocages are possibly promising devices for NT sensors based on their electronic and structural properties.