The nominal nature of the gerund reveals itself at the syntactic level, namely in its combinability and functions. Like the noun, the gerund can be preceded by:
1) a preposition, e.g.:
I'm tired of watching television
2) a noun in the genitive case or a possessive determiner
I remember Tom's complaining about the poor service in this hotel
Like the noun, the gerund can perform the functions of the following parts of the sentence.
1. Subject, e.g.:
Swimming is my favourite sport
2. Object, e.g.:
I like swimming
3. Predicative, e.g.:
My favourite sport is swimming
4. Attribute, both prepositional and non-prepositional. Cf: He was born with the gift of winning hearts