Effects of N-seeding in L-mode experiments in ASDEX Upgrade and JET are analysed numerically with the SOLPS5.0 code package. The modelling yields 3 qualitatively different radiative regimes with increasing N concentration, when initially attached divertor conditions are studied. The radiation pattern is observed to evolve asymmetrically, increasing first in the inner divertor, then in the outer divertor, and finally on closed field lines above the X-point. Scaling of the radiative regimes is observed to be sensitive to cross-field drifts, divertor geometry and the initial divertor regime in the absence of seeding. The scaling of the radiated power with the divertor neutral density is similar to an experimental scaling law for H-mode radiation, for values up to 70% of the heating power. The same parametric dependency is not observed at higher radiated powers or in simulations without drifts.