In Channel Management Permissions, "People who can create private channels" must be set to "Everyone, plus multi-channel guests (Default)" for installation.
Nightfall Enterprise DLP for Slack has 3 User Token Scopes:
discovery:read, discovery:write, groups:write
Nightfall Enterprise DLP for Slack has 12 Bot Token Scopes:
channels:join, channels:read, chat:write, commands, files:read, files:write, groups:read, groups:write, im:read, im:write, mpim:read, users:read
Nightfall Pro DLP for Slack has 6 User Token Scopes:
channels:read, channels:write, chat:write, files:write, groups:read, users:read
Nightfall Pro DLP for Slack has 16 Bot Token Scopes:
channels:history, channels:join, channels:read, chat:write, commands, files:read, files:write, groups:history, groups:read, groups:write, im:history, im:read, im:write, mpim:history, mpim:read, users:read