The aim of this study is to compare the differences between four maize hybrids in terms of nutrient determination by portable near-infrared reflectance spectrometer (pNIRS) and chemical analysis; each of the hybrids was grown in the same locality from 2018 to 2020. The topic relates to the variability of the feed value of maize being an important feedstuff in livestock nutrition. The nutritional values determined by pNIRS in comparison with the chemical analysis were higher (P < 0.001) in starch and ash content but lower in dry matter, neutral detergent fibre and crude protein (CP) content. The digestibility levels of neutral detergent fibre and the net energy of lactation as well as the potential milk production per hectare in relation to each tonne of dry matter were also lower. According to this result, it would be necessary to calibrate all tested indicators for a given spectrometer. However, the pNIRS results are useful for evaluating nutrient variability; the standard deviation of the values found in pNIRS was mostly lower than that determined chemically. The pNIRS results are also useful for making practical adjustments to the total mixed rations when calculated from actual chemical analysis if the correlation between the two methods is used; the correlation between the pNIRS and chemical results was found to be significant (P < 0.05) in terms of all the indicators.