CRA pays them on family net income from the base year (as for the Canada Child Benefit).
NWT Child Benefit
A yearly amount for children under 6 ($815 for one, $1,467 for two) and another for children 6 to 17 ($652 for one, $1,174 for two), paid in full up to $30,000 of family income and reduced in a straight line to nothing at $80,000. A parent with shared custody gets half the difference the shared children make. It comes with the CCB each month.[1]
What it does not do
The Senior Citizen Supplementary Benefit and the Senior Home Heating Subsidy are run by the territory and are not modelled. See income tax in the Northwest Territories.