Antimicrobial　packaging　is　important　for　preventing　food　spoilage　and　extending　shelf　life.　Herein,　antimicrobial　core-shell　nanofiber　films　were　fabricated　via　coaxial　electrospinning　with　pullulan/nanochitin-nisin　complexes　as　the　core　and　gelatin-zein　as　the　shell.　Particle　size　and　zeta　potential　analyses　confirmed　the　successful　formation　of　nanochitin-nisin　complexes.　Fourier-transform　infrared　spectrometry　(FTIR)　revealed　binding　via　electrostatic　interactions　and　hydrogen　bonding.　The　suitable　viscosity,　conductivity,　and　surface　tension　of　the　spinning　solutions　ensured　good　spinnability,　yielding　uniform　nanofibers,　as　observed　using　scanning　electron　microscopy.　FTIR　and　X-ray　diffraction　analyses　indicated　that　hydrogen　bonding　stabilized　the　core-shell　structure　without　altering　the　crystallinity　of　biopolymers.　The　resulting　films　exhibited　enhanced　thermal　stability,　mechanical　strength,　reduced　water　vapor　permeability　(by　~40　%),　and　improved　hydrophobicity.　The　antibacterial　activities　against　Staphylococcus　aureus　ATCC　25923　and　Escherichia　coli　ATCC　25922　were　comparable　to　those　of　uniaxial　nanofiber　films.　After　15　days　of　refrigerated　storage　at　4　°C,　sea　bass　fillets　wrapped　in　the　films　showed　reductions　in　total　volatile　basic　nitrogen,　total　viable　counts,　and　thiobarbituric　acid　reactive　substances　by　approximately　50　%,　90　%,　and　75　%,　respectively,　compared　to　those　wrapped　in　uniaxial　nanofiber　films.　These　findings　indicate　the　potential　of　the　core-shell　nanofiber　films　for　antimicrobial　food　packaging　applications.　©　2025　Elsevier　Ltd