After you create your field using Add-PnPField, you need to get that field using Get-PnPField and set the default value as below:

$field = Get-PnPField -List CustomList -Identity "BoolField"
$field.DefaultValue = "0"
$field.Update()
Invoke-PnPQuery

Also, you can use PnPFieldFromXml itself to create a boolean field with No as default value as :

$fieldXml = "<Field Type='Boolean' Name='TestBool' StaticName='TestBool' DisplayName='Test Bool'><Default>0</Default></Field>"
Add-PnPFieldFromXml -FieldXml $fieldXml

After you create your field using Add-PnPField, you need to get that field using Get-PnPField and set the default value as below:

$field = Get-PnPField -List CustomList -Identity "BoolField"
$field.DefaultValue = "0"
$field.Update()
Invoke-PnPQuery

Also, you can use PnPFieldFromXml itself to create a boolean field with No as default value as :

$fieldXml = "<Field Type='Boolean' Name='TestBool' StaticName='TestBool' DisplayName='Test Bool'><Default>0</Default></Field>"
Add-PnPFieldFromXml -FieldXml $fieldXml

References - Add-PnPFieldFromXml

Create fields using CSOM

After you create your field using Add-PnPField, you need to get that field using Get-PnPField and set the default value as below:

$field = Get-PnPField -List CustomList -Identity "BoolField"
$field.DefaultValue = "0"
$field.Update()
Invoke-PnPQuery

After you create your field using Add-PnPField, you need to get that field using Get-PnPField and set the default value as below:

$field = Get-PnPField -List CustomList -Identity "BoolField"
$field.DefaultValue = "0"
$field.Update()
Invoke-PnPQuery

Also, you can use PnPFieldFromXml itself to create a boolean field with No as default value as :

$fieldXml = "<Field Type='Boolean' Name='TestBool' StaticName='TestBool' DisplayName='Test Bool'><Default>0</Default></Field>"
Add-PnPFieldFromXml -FieldXml $fieldXml