nuget: dll is not inside lib folder

I am trying to create a nuget package that depends on a custom .dll. For that, I use this code:

NuGet_v5.2.0.exe pack Cmon.csproj -Prop Configuration=Release -IncludeReferencedProjects

I am greeted with:

WARNING: NU5100: The assembly 'content\lib\Request32\libcurl.dll' is not inside the 'lib' folder and hence it won't be added as a reference when the package is installed into a project. Move it into the 'lib' folder if it needs to be referenced.

For every dll I depend on. Apperently, lib under which I put Request32 and Request64 is not the one nuget looks for. Where should I put my dll dependencies? This is my folder structure printer with tree /F . command:

│   Cmon.csproj│   Cmon.nuspec│   nuget.exe│   nuget_v5.2.0.exe│   packages.config│├───bin│├───Debug│││   Cmon.dll│││   Cmon.pdb│││   Newtonsoft.Json.dll│││   Newtonsoft.Json.xml│││   System.IO.dll│││   System.Runtime.dll│││││└───lib││├───Request32│││       libcurl.dll│││       Request32.dll│││       zlib1.dll│││││└───Request64││               libcurl.dll││               Request64.dll││               zlib1.dll│││└───Release││   Cmon.dll││   Cmon.pdb││   Newtonsoft.Json.dll││   Newtonsoft.Json.xml││   System.IO.dll││   System.Runtime.dll│││└───lib│├───Request32││       libcurl.dll││       Request32.dll││       zlib1.dll│││└───Request64│                   libcurl.dll│                   Request64.dll│                   zlib1.dll│├───Conf│       Access.cs│├───EMessage│       EMessage.cs│├───lib│├───Request32││       libcurl.dll││       Request32.dll││       zlib1.dll│││└───Request64│           libcurl.dll│           Request64.dll│           zlib1.dll│├───obj│├───Debug│││   Cmon.csproj.CopyComplete│││   Cmon.csproj.FileListAbsolute.txt│││   Cmon.csprojAssemblyReference.cache│││   Cmon.dll│││   Cmon.pdb│││││└───TempPE│└───Release││   Cmon.csproj.CopyComplete││   Cmon.csproj.FileListAbsolute.txt││   Cmon.csprojAssemblyReference.cache││   Cmon.dll││   Cmon.pdb│││└───TempPE└───Properties        AssemblyInfo.cs

Cmon.nuspec content:

<?xml version="1.0" encoding="utf-8"?><package ><metadata><id>$id$</id><version>$version$</version><title>$title$</title><authors>Me</authors><owners>$author$</owners><requireLicenseAcceptance>false</requireLicenseAcceptance><license type="expression">MIT</license><description>Cmon Code</description><copyright>Copyright 2021</copyright></metadata></package>