The atmospheric concentration of nitrous oxide (N₂O) has increased significantly since 1800, mainly due to agricultural activities. However, due to their large area, nutrient-poor natural soils, including those in the (sub-) Arctic, also play a crucial role in N₂O emissions and consumption. Despite their importance, these soils have been understudied, due to methodological limitations in detecting low fluxes. Our study addresses this knowledge gap by testing a fast-responding portable gas analyser (PGA; Aeris MIRA Ultra N₂O/CO₂) combined with manual chambers (height and diameter: 25 cm) for measuring N2O fluxes from a nutrient-poor, sub-Arctic peatland. Our results show that this setup can detect and quantify low N₂O flux rates, with a mean and standard error of -0.61±0.08 µg N₂O-N  m^-2h^-1 for a 5 min closure time, as observed in our study. More than 70 % of the measured N₂O fluxes exceeded the minimum detectable flux (0.027±0.0002 µmol m^-2h^-1), which varied according to chamber closure time. Our study highlights the importance of using fast-responding analysers to measure low N₂O fluxes and improve our understanding of diverse N₂O flux dynamics. For nutrient-poor soils, we recommend a chamber closure time of approximately 5 min. We also found that a non-linear flux calculation model yielded better results and was broadly applicable, including cases where data were linearly distributed. Overall, our study demonstrates the potential of fast-responding analysers to improve our understanding of N2O flux dynamics in nutrient-poor soils.