Nipsative assessments are a combination of both 'ipsative' and 'normative' type assessment. These types of assessments are rare and new in the test publishing industry and are a useful way of identifying reliable norm groups (see section on 'norms' for more information).
Normative questionnaires simply ask individuals to rate a statement (or question) they are presented with on a scale of 1 to 5 indicating their level of disagreement or agreement. Ipsative type questions require individuals to choose a statement they most agree with and one statement that they most disagree with from a group of 3 or 4 equally desirable statements (for more information see 'Ipsative tests'). A 'nipsative' type assessment combines both of these styles into one and requires the individual to both indicate their level of agreement with each statement, as well as rank the statements in terms of their agreement with them.
The best advice when taking these assessments is to be as honest as possible. If you attempt to distort these questionnaires, the results can appear sporadic with certain consistency and desirability scales (contained within these assessments) giving away your style of response.