The case system of Old and Modern North Russian is based on a typical nominative-accusative pattern. However, these languages utilize nominative objects in some syntactic constructions. The rigid correlation between nominative object marking and particular syntactic structures shows that nominative object marking is motivated and conditioned by a certain syntactic environment. This paper explores how the nominative object is syntactically licensed by comparing North Russian nominative object constructions to similar constructions in Baltic and Finnic languages. Special attention has been paid to the similarity between nominative object constructions and be-possessive constructions in Baltic, Finnic, and North Russian. Nominative object constructions, like be-possessive constructions, feature a syntactic structure in which a functional head assigns an oblique case to the external argument. The object then may appear in the nominative in an agreement relation with the matrix Tense. The presence of a functional head that licenses oblique subject appears to condition the nominative object phenomenon. I identify this functional head as a prepositional complementizer. This kind of environment typically appears in nominal phrase structures. Possessive Agentive Constructions, one type of the nominative object constructions examined in this paper, feature either verbal nominalization or the extension of the nominal structure. Non-finite Impersonal Constructions, the other nominative object sentence type, do not contain a nominalized structure, but they are historically derived from the be-possessive structure and still provide an environment in which the embedded subject is oblique case-marked, which makes it possible for the object to appear in the nominative. If the accusative-assigning functional head v is specified as [+specific], [+animate], etc., only object nouns with the relevant features may be assigned the accusative by v. Object nouns without the relevant features are licensed by the matrix Tense with the nominative case. The variation of predicate agreement with the nominative object in the given constructions is explained in terms of Multiple Agree: when agreement is established between a Probe and multiple Goals, phi-agreement may be morphologically realized in favor of one of the Goals and case may be realized on another Goal. The case-marking mechanism proposed in this paper is very similar to the case-marking strategy in Tense/Aspect-split ergative languages, in which the nominative object is productive. Baltic, Finnic, and North Russian nominative object constructions as well as ergative constructions may be typologically defined based on the presence of a prepositional complementizer that assigns the oblique case to the external argument, which conditions the licensing of the nominative object. This typology is more general and universal than the be-language vs. have-language and NOM-ACC vs. ERG-ABS dichotomies.