XBRL Item – Ex-101.INS-XBRL Instance Document - nick-20180331.xml -

XBRL Item – Ex-101.SCH-XBRL Taxonomy Extension Schema Document - nick-20180331.xsd -

XBRL Item – Ex-101.CAL-XBRL Taxonomy Extension Calculation Linkbase Document - nick-20180331_cal.xml -

XBRL Item – Ex-101.LAB-XBRL Taxonomy Extension Label Linkbase Document - nick-20180331_lab.xml -

XBRL Item – Ex-101.PRE-XBRL Taxonomy Extension Presentation Linkbase Document - nick-20180331_pre.xml -

XBRL Item – Ex-101.DEF-XBRL Taxonomy Extension Definition Linkbase Document - nick-20180331_def.xml -

XBRL Item – Ex-101.INS-XBRL Instance Document - nick-20171231.xml -

XBRL Item – Ex-101.SCH-XBRL Taxonomy Extension Schema Document - nick-20171231.xsd -

XBRL Item – Ex-101.CAL-XBRL Taxonomy Extension Calculation Linkbase Document - nick-20171231_cal.xml -

XBRL Item – Ex-101.LAB-XBRL Taxonomy Extension Label Linkbase Document - nick-20171231_lab.xml -

XBRL Item – Ex-101.PRE-XBRL Taxonomy Extension Presentation Linkbase Document - nick-20171231_pre.xml -

XBRL Item – Ex-101.DEF-XBRL Taxonomy Extension Definition Linkbase Document - nick-20171231_def.xml -

XBRL Item – Ex-101.INS-XBRL Instance Document - nick-20170930.xml -

XBRL Item – Ex-101.SCH-XBRL Taxonomy Extension Schema Document - nick-20170930.xsd -

XBRL Item – Ex-101.CAL-XBRL Taxonomy Extension Calculation Linkbase Document - nick-20170930_cal.xml -

XBRL Item – Ex-101.LAB-XBRL Taxonomy Extension Label Linkbase Document - nick-20170930_lab.xml -

XBRL Item – Ex-101.PRE-XBRL Taxonomy Extension Presentation Linkbase Document - nick-20170930_pre.xml -

XBRL Item – Ex-101.DEF-XBRL Taxonomy Extension Definition Linkbase Document - nick-20170930_def.xml -

XBRL Item – Ex-101.INS-XBRL Instance Document - nick-20170630.xml -

XBRL Item – Ex-101.SCH-XBRL Taxonomy Extension Schema Document - nick-20170630.xsd -

XBRL Item – Ex-101.CAL-XBRL Taxonomy Extension Calculation Linkbase Document - nick-20170630_cal.xml -

XBRL Item – Ex-101.LAB-XBRL Taxonomy Extension Label Linkbase Document - nick-20170630_lab.xml< -

XBRL Item – Ex-101.PRE-XBRL Taxonomy Extension Presentation Linkbase Document - nick-20170630_pre.xml -

XBRL Item – Ex-101.DEF-XBRL Taxonomy Extension Definition Linkbase Document - nick-20170630_def.xml -