Example of the fitting procedure for object JADES-NS-00016745 (Fig. 1). Although the final combination of all exposures (left) was used for our initial visual inspection and sample selection, the pixels in this spectrum are highly correlated. Instead of using this combined spectrum, we simultaneously fit to all individual exposures obtained. In the case of JADES-NS-00016745, two exposures were taken per nodding position, resulting in six independent measurements for one three-point nodding pattern with NIRSpec. To account for the undersampled PSF of NIRSpec, we performed our modelling in the detector plane, propagating parametric models to the exact same location on the detector as the observed data. The likelihood is then computed from the combination of all residual images. Pixels flagged by the reduction pipeline as affected by cosmic rays are masked and shown in grey.