We present here the study on magnetic properties and their relation to the electronic structure for c-axis oriented LaNiO₃ films deposited on LaAlO₃ single crystals using the rf-magnetron sputtering. Swift heavy ion irradiation induced annealing alters the unusual temperature dependent magnetic behaviour of pristine film to the paramagnetic one. X-ray absorption spectroscopic measurements, performed at O K-edge and Ni L-edge, reveal that NiO hybridization is increased after the initial irradiation. Charge-transfer multiplet calculations of the Ni L-edge indicate that variation of magnetic behaviour can be related to the NiO hybridization strength inducing a further variation in Ni spin state.