limit_except

Limits allowed HTTP methods inside a location. The method parameter can be one of the following: GET, HEAD, POST, PUT, DELETE, MKCOL, COPY, MOVE, OPTIONS, PROPFIND, PROPPATCH, LOCK, UNLOCK, or PATCH. Allowing the GET method makes the HEAD method also allowed. Access to other methods can be limited using the ngx_http_access_module and ngx_http_auth_basic_module modules directives:

limit_except GET {
    allow 192.168.1.0/32;
    deny  all;
}

Please note that this will limit access to all methods except GET and HEAD.