Liquid nitrogen has a density of 808 kg/m³…

Step 1. The liquid. One mole fills $\dfrac{M}{\rho} = \dfrac{0.028\ \text{kg/mol}}{808\ \text{kg/m}^3} = 3.47 \times 10^{-5}\ \text{m}^3\text{/mol}$. Shared among $N_A$ molecules, each has $\dfrac{3.47 \times 10^{-5}\ \text{m}^3\text{/mol}}{6.02 \times 10^{23}\ \text{mol}^{-1}} = 5.76 \times 10^{-29}\ \text{m}^3$. The cube root is $3.86 \times 10^{-10}$ m, that is $0.386$ nm.

Step 2. The gas. $\dfrac{k_BT}{p} = \dfrac{1.38 \times 10^{-23}\ \text{J/K} \times 300\ \text{K}}{101.3 \times 10^3\ \text{Pa}} = 4.09 \times 10^{-26}\ \text{m}^3$. The cube root is $3.44$ nm.

Step 3. Compare. $\dfrac{3.44\ \text{nm}}{0.386\ \text{nm}} = 8.9$.