For those of you who have been trying to automate anything related to Microsoft Teams, let me tell you that there is a new PowerShell Module in town: Microsoft Teams 0.9.0 which you can install with the following command:

1    Install-Module MicrosoftTeams

Now to automate the channel creation In A Team you can simply:

Create a file createTeamChannel.ps1 with the following contents:

 1    Param
 2    (
 3        [Parameter(Mandatory = $true)][string]$username,
 4        [Parameter(Mandatory = $true)][securestring]$password,
 5        [Parameter(Mandatory = $true)][string]$tenantId,
 6        [Parameter(Mandatory = $true)][string]$teamName,
 7        [Parameter(Mandatory = $true)][string]$channelName)
 8
 9    # Create PSCredential
10    $credential = New-Object System.Management.Automation.PSCredential($username, $password)
11
12    # Connect to Microsoft Teams
13    Connect-MicrosoftTeams -TenantId $tenantId -Credential $credential
14
15    # Get the Team
16    $team = Get-Team | Where-Object { $_.DisplayName -eq $teamName}
17
18    if ($team) {
19        # Create the new Team Channel
20        New-TeamChannel -GroupId $team.GroupId -DisplayName $channelName -Description $channelName
21    }
22    else {
23        throw "Team: $teamName does not exist."
24    }

Run the following command in PowerShell

1    $password = ConvertTo-SecureString "YOUR PASSWORD" -AsPlainText -Force
2    .\createTeamChannel.ps1 username@tenant.com $password $tenantId MonitoringIssues Incident101

Hope it helps!