unfortunately, you cannot update multiple nodes inside xml, you can use loop:
select @i = @xml.value('count(Nodes/Node)', 'int')
while @i > 0
begin
set @xml.modify('insert <Phone>111</Phone> into (/Nodes/Node)[sql:variable("@i")][1]')
set @i = @i - 1
end
select @xml
or you can reconstruct your xml like this:
select
111 as Phone,
t.c.value('Name[1]', 'nvarchar(max)') as Name
from @xml.nodes('Nodes/Node') as t(c)
for xml path('Node'), root('Nodes')