Rubuta ci gaba don wannan sakin layi - Nemisz ya shiga OHL ta Windsor Spitfires a 2006 <unk> 07, yana yin rikodin maki 34 a wasanni 62. Ya inganta zuwa maki 67 a wasanni 68 tare da Spitfires a shekara mai zuwa, yana samun kyautar ƙungiyar don sadaukarwa da ƙuduri. Lokacinsa ya jagoranci Calgary Flames don zaɓar shi tare da zaɓaɓɓen zagaye na farko, 25th gaba ɗaya, a 2008 NHL Entry Draft
, wanda ya tsara shi ya zama mai iko gaba. Nemisz ya kafa aikinsa tare da Spitfires a 2008-09, inda ya zira kwallaye 36 da maki 77 a wasanni 65, yayin da ya kara maki 20 a wasanni 20 yayin da ya taimaka wa tawagarsa ta kama J. Ross Robertson Cup a matsayin zakarun OHL. Daga nan sai ya ci gaba da zira kwallaye guda shida a gasar Memorial Cup ta 2009 yayin da Spitfires suka ci Kelowna Rockets na Yammacin Hockey League don lashe gasar zakarun kasa.